#8 Dimple -Fuel Tanks

I feel like I have cranked down my DRDT pretty darn tight to dimple these #8 screw holes that attach the fuel tank skin to the spar, but on the same token the screws themselves are not sitting completely flush with the skin. I have included pics below. Are these dimples adequate, or do I reeeaaalllyyy need to crank the dies together to get more depth? I am a bit hesitant to squeeze them any tighter without a more experienced opinion.

http://1drv.ms/1kZKOKb

screw dimples

Something doesn't look right in your pic. It looks like a no 8 screw in a no 6 dimple. Are your dies are making good contact? What brand dies are you using? These large dimples do highlight the difference in the dies.

That dimple is definitely not correct. Stop and evaluate with scrap before proceeding. You know that "trim kit" that Vans includes in the empennage kit. Find a piece that is the same thickness as the tank skin (flawed info removed) and make it right. I promise, it is there for your exploration.

scard said:

That dimple is definitely not correct. Stop and evaluate with scrap before proceeding. You know that "trim kit" that Vans includes in the empennage kit. Find a piece that is the same thickness as the tank skin (.040 I think) and make it right. I promise, it is there for your exploration.

Click to expand...

Tank skins are 0.032.

Also, if you tighten the gap between the dies in your DRDT-2 too much, the handle won't go over center, and you lose a lot of dimpling force.

Test tokens

scard said:

That dimple is definitely not correct. Stop and evaluate with scrap before proceeding. You know that "trim kit" that Vans includes in the empennage kit. Find a piece that is the same thickness as the tank skin (.040 I think) and make it right. I promise, it is there for your exploration.

Click to expand...

After you get a good dimple with scrap, cut sample tokens from each thickness scrap and make a sample dimple cor each size dimple die. You'll need them to get the countersinks the correct depth. They come in useful for fitting parts.

DUH

You mean your supposed to use #8 dies for a #8 screw??? I put mine away in the wrong spot on my block and grabbed the #6 by mistake. They look lots better with the right die.

how do I delete a whole thread again??

Read the directions too.

As I recall, for these dimples, Van's states in the directions that you get a little better & sharper dimple using a dead blow hammer on a dimpling die setup than with a squeezer. I did that and it came out fine.